Theres no doubt a modded 430 can take a car to 150. I recently built a 430 out of a 67 Riviera GS to put in my 72 Riviera. The 67's came with big port heads and once you port them further, the engine REALLY comes alive.
My current combo includes goodies like full length headers with 2" primaries, a single plane intake with a Holley 850DP, big Mutha Thumpr cam and a Th400 with a 2500 stall.
I can quickly bury my speedo past the 125 mark and with my 3.42 gears and 28" tall tires I've only taken it up to 5500 rpms in third gear which equates to about 130ish with another 500rpm to go in the usable power band.
So 150 in a better geared, lighter Skylark, is easily attainable.

I suppose you're going to have to excuse my crude image editing skills, but I believe a picture says a thousand words. Until someone shows me otherwise, I'm convinced that the posters skylark would have to bear an uncanny resemblance to my fantasy buick below to crack 150mph. It would also explain why he has any business racing Supras.